The present invention relates to planning and guidance of electrophysiology interventions, and more particularly to personalized and interactive planning of electrophysiology interventions using a fast and personalized computational model of the cardiac electrophysiology along with a model of electrocardiogram (ECG) signal generation.
Sudden cardiac death (SCD) is responsible for over 300,000 deaths per year in the United States. Severe cardiac arrhythmias, such as ventricular tachycardia (VT) or ventricular fibrillation (VF), are the most common causes of SCD. Currently, implantable cardioverter-defibrillator devices (ICD) are the primary treatment of choice for patients at high risk for VT or VF. These devices prevent life-threatening VT/VF events by automatically sending strong defibrillator shocks when VT/VF is detected. However, the morbidity associated with ICD shocks is high and ICDs do not provide complete protection against SCD. When arrhythmias become incessant or too severe, an alternative therapy becomes necessary.
Ablation procedures for cardiac arrhythmias have proven to be successful for a large variety of cardiac electrophysiology troubles. Atrial fibrillation (Afib), VT, or VF, for example, can be treated, or at least controlled, in several classes of patients. The general idea behind ablation therapy is to destroy the cells that trigger the arrhythmias. These cells can be ectopic, i.e., they trigger uncontrolled electrical signals spontaneously, or exits points of slow conducting pathways that can be found, for example, around or within myocardium scars. The success of the ablation therapy relies on the ability of the electrophysiologist to identify the arrhythmogenic regions. While Afib ablation has become systematic in most patients, finding the regions to ablate in post myocardium infarction (MI) patients is extremely challenging due to the variability in scar geometry and local tissue substrate. Current practice is still lacking of a systematic clinical strategy, which may explain the rather unsatisfactory success rate of ablation therapies for VT (from 50% to 90%).
Congestive Heart Failure (CHF) is a dramatically widespread disease, affecting more than 23 million people worldwide, and more than 5.8 million in the United States. CHF symptoms are various and affect the patients to different degrees. The New York Heart Association (NYHA) proposed a classification of patients in four groups, from minimally or mildly symptomatic (Class I and II) to moderately or severely symptomatic (Class III and IV). Patients with heart failure often present dyssynchronous ventricular contraction. Cardiac Resynchronization Therapy (CRT) is used to treat this condition by artificially pacing the cardiac muscle through a pulse generator (pacemaker) and multiple leads, including a left ventricle (LV) lead, a right ventricle (RV) lead, and a right atrial (RA) lead. In combination with optimal medical therapy (with or without a defibrillator), CRT has been proven to reduce the risk for hospitalization of CHF patients, and to improve the heart conditions in NYHA Class I and II patients. A recent study showed that the combined use of CRT and an implantable cardioverter defibrillator (ICD) has significant success in the treatment of patients with left bundle branch block (LBBB), a cardiac conduction anomaly detectable with ECG. However, 30% of patients do not respond to the therapy although they are within the guidelines.
One challenge facing the delivery of effective CRT is the left ventricular lead placement. The coronary venous anatomy often limits access to the target pacing area. In addition, the presence of localized scar tissue in the region of the LV lead tip may alter the response to the treatment. Acute haemodynamic studies demonstrate that the increase in the patient's heart conditions is less robust when the LV is paced in an area near a scar. Furthermore, localized LV dyssynchrony, which is common in heart failure patients and detectable by ECG, has a significant impact on overall CRT effectiveness. The interaction between the region of maximal dyssynchrony and the presence of scar tissue adjacent to the LV lead tip has important implications for determining optimal pacing sites. Accordingly, a predictive framework is desirable to select responders and optimize lead configuration for CRT.
In view of the foregoing, there is a need for efficient tools for improving electrophysiology interventions, such as CRT and ablation procedures, in terms of maximizing outcomes, decreasing risks and minimizing intervention time.